S12 Clock, Reset and Power Management Unit (S12CPMU)
Table 7-11. CPMUCOP Field Descriptions
Field
Description
7
Window COP Mode Bit — When set, a write to the CPMUARMCOP register must occur in the last 25% of the
selected period. A write during the first 75% of the selected period generates a COP reset. As long as all writes
occur during this window, $55 can be written as often as desired. Once $AA is written after the $55, the time-out
logic restarts and the user must wait until the next window before writing to CPMUARMCOP. Table 7-12 shows
the duration of this window for the seven available COP rates.
WCOP
0 Normal COP operation
1 Window COP operation
6
COP and RTI Stop in Active BDM Mode Bit
RSBCK
0 Allows the COP and RTI to keep running in Active BDM mode.
1 Stops the COP and RTI counters whenever the part is in Active BDM mode.
5
Write Mask for WCOP and CR[2:0] Bit — This write-only bit serves as a mask for the WCOP and CR[2:0] bits
WRTMASK while writing the CPMUCOP register. It is intended for BDM writing the RSBCK without changing the content of
WCOP and CR[2:0].
0 Write of WCOP and CR[2:0] has an effect with this write of CPMUCOP
1 Write of WCOP and CR[2:0] has no effect with this write of CPMUCOP.
(Does not count for “write once”.)
2–0
CR[2:0]
COP Watchdog Timer Rate Select — These bits select the COP time-out rate (see Table 7-12). Writing a
nonzero value to CR[2:0] enables the COP counter and starts the time-out period. A COP counter time-out
causes a System Reset. This can be avoided by periodically (before time-out) initializing the COP counter via
the CPMUARMCOP register.
While all of the following four conditions are true the CR[2:0], WCOP bits are ignored and the COP operates at
24
highest time-out period (2
cycles) in normal COP mode (Window COP mode disabled):
1) COP is enabled (CR[2:0] is not 000)
2) BDM mode active
3) RSBCK = 0
4) Operation in special mode
Table 7-12. COP Watchdog Rates
COPCLK
Cycles to time-out
(COPCLK is either IRCCLK or
OSCCLK depending on the
COPOSCSEL bit)
CR2
CR1
CR0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
COP disabled
2 14
2 16
2 18
2 20
2 22
2 23
2 24
S12P-Family Reference Manual, Rev. 1.13
218
Freescale Semiconductor
FREESCALE [ Freescale ]
